Brake



Feb. 25, 1936. R. c. LI'P. TURGOT BRAKE Original Filed. June 25, 19312Sheets-Sheet 1 INVENTOR. ,(bberf (liar/0i [011/5 Pierre Turyof WAyT0RNi YS.

Feb. 25, 1936.

R. C. L. P. TURGOT BRAKE Original Filed June 25, 1951 2 Sheets-Sheet 272/ Ill/ INVENTOR. mm (bar/0510MB P/krreTu 1302 v dmdi TTORNEYJ PatentedFeb. 25, 1936 UNITED STATES BRAKE Robert Charles Louis Pierre Turgot,Saint Etienne de Cuisnes, Savoie, France, assignor, by mesneassignments, to Bendix Brake Company, South Bend, Ind., a corporation ofIllinois- Original application June 23, 1931, Serial lilo. 546,342.Divided and this application March 9, 1934, Serial No. 714,802. InFrance June 23,

3 Claims. (Cl. 188-795) This invention relates to brakes and moreparticularly to adjusting means for brake operating devices.

All hydraulic systems in which the desired operation is effected by theincrease in the pressure of a fluid are subject to a serious weakness,namely, that the system is incapacitated by the occurrence of a leak inany part of the system, whereby the transmitting fluid may be lost andits pressure dissipated; .In hydraulic brake systems this weakness isdoubly important due to the great danger under which the failure of abraking system places the occupants of a vehicle. This has beenrecognized in railway braking, resulting in the standard and requiredequipm'ent of trains with reduction-pressure braking systems, butheretofore no method has been successfully and practically worked outfor utilizing this reduction-pressure method for braking automotivevehicles. 7

It is, therefore, an object of the present invention to provide noveland improved hydraulic braking means which "operate to effect brakeapplication on a reduction in the pressure of the fluid in the system.

It is another object of the invention to provide a reduction pressurebraking system utilizing spring means both for brake applicationandbrake release. 7

Anotherobject of the invention is to provide a braking system whereinthe fluid is used to transmit pressures between two springs which arenormally balanced.

Another object of the invention is to provide a braking system in whichmanual operation to initiate braking causes expansion of the fluid' 1provide novel and improved manually-operable means under control of thebrake shoes with respect to the drum, such adjusting means actingthrough the entire braking system to simultaneously adjust all the partsthereof.

Other objects and features of novelty will be apparent from thefollowing detailed description when taken in connection with theaccompanying drawings. It is to be expressly understood however, thatthe drawings are for purposes-of illustration only and are not designedas a definition of the limits of the invention, reference being had forthis purpose to the appended claims.

In the drawings wherein similar reference characters refer to like partsthroughout the several views:

Figure 1 is a vertical section of a control device according to theinvention, in this diagram the group of transmitting elements beingshown on a scale smaller than that of the receiving elements;

Figure 2 is a vertical section of another structure illustrating acontrol transmitting device constructed according to the invention;

Figure 3 is a view in elevation showing an application of the device toan automobile brake;

Figure 4 is a view in elevation showing an application of the device toanother automobile brake;

Figure 5 is a longitudinal section showing the adaptation of a similarcontrol device to the front wheel of an automobile Figure 6 is anelevation of an adjusting device for the controldevice;

Figure '7 is a side view of this same arrangement the same being partlyin section;

Figures 8 and 9 are views, similar to Figures 6 and 7, of a modificationof the adjusting device.

According to the form of construction shown in Figure 1, the controldevice is composed of two groups of elements, one, A, which is thetransmitter, is situated preferably at the actual controlling spot anddirectly connected with the operating mechanism, either lever or pedal.The other, B, which is the receiver, is situated at any convenientdistance from the former and directly coupled to the controlledmechanism, brake jaws or any other mechanism. These two group ofelements, A and B, are connected by a piping C containing thetransmitting fluid.

In the transmitting group A, the pipe C enters a cylinder l formedintegrally with a housing 2 acting, preferably, as a tank for the liquidand also providing trunnions for pivotally mounting the pedal, the leveror any other control element 3. A piston 4 slides in the cylinder I. Thecylinder I communicates with the tank 2 through a hole 5 in the wall ofthe said cylinder when this port is uncovered by the piston 4. A smallcup 6 is pressed against the face of the piston on the insures thatthere shall be no leakage in chamber 8. A lever 9, fixed to a crossshaft I0 controls piston 4 through a rod II. A large compression springl2 bears at one end on lever 9 and at the other'end on the housing 2-and urges piston 4 in the direction of the arrow The shaft l0 protrudesthrough one side of the housing 2 and the pedal 3 is fixed on this shaftoutside housing 2. A screw l3 screwed into a plank or a frame l4supplies means for adjusting the rest position of pedal 3 by hand.

, The piping C is connected, at its other end, to a cylinder l5 whichserves as a housing for the group of receiving elements B. A piston I5is slidably mounted in cylinder l5. On the face of the piston which ison the same side as the piping C, a. small cup I! is mounted, thuspreventing any leakage of fluid in space 18. A socket l9, perforatedwith holes 20, is placed against the small cup I! and retained by aspring 2| which rests on the 'cover of the cylinder l5. This socketlimits the travel of piston IS in the directionof the arrow f Piston I6is connected to a rod 22 by means of a ball joint 23 which is integralwith this rod. The joint23 is loosely enclosed in piston l6 so that itmay be free to oscillate. A plug 24 is set, for instance, on piston ISin order to prevent the ball joint 23 from leaving its recess. At theother end of rod 22 a yoke 25 is secured and connected with the elementsto be controlled (this yoke 25 is screwed on to the right in the examplerepresented in Figure 1).

This yoke is connected to the element or elements to be controlled. Forinstance in the case of vehicle brakes shown in Figures 4 and 5, tworods 26 and 21 are articulated both at one end in yoke 25 and on theother hand on the brake jaws 28 and 29.

Rod 22 can slide (Figure 1) in a plug 30 closing the end of cylinder l5.This plug 30 is screwed onto the cylinder for instance and locked bymeans of a locking piece 3|. A powerful spring 32 bears at one end onpiston l6 and at the other end on a washer 33 which bears against theplug 30. This control gear is, preferably, fitted with an automaticadjusting device. in the event of there being any wear of the elementcontrolled, which is particularly the case in the case of a brakecontrol.

In the example represented in Figure 1, a ring 34, provided with teeth35, is fixed on rod 22 by means such as a cotter pin 36. This ring 34engages with another ring 31 free to turn and slide on rod 22. The teethon these two rings are so arranged that ring 31 can drive ring 34 onlyin one direction. Ring 31 is connected to the plug 30 through rods 38articulated by pins 39 and 40 on the said ring 31 and on plug 30. Inthis way when ring 31 moves longitudinally in the direction of arrow frods 38 compel it to turn about rod 22 in thedirection of arrow f. Aspring 4| which bears on the one hand on yoke 25 and on the other onring 31 keeps the latter in contact with ring 34.

Leather or rubber bellows 42 are attached at one end to cylinder l5 andat the other end to plug 30 to protect the assembly from dust and water.This device includes, in addition, at the upper end of the cylinder l5,a port 43 closed by a screw-plug 44 permitting the evacuation of the airor gases contained in cylinders l5 and l and the pipe line C whenfilling.

Operation is as follows: Tank 2, cylinders l "same side as piping C by asmall spring I and and i5 and pipe line C being full of liquid, occupypositions indicated for each of them in Figure 1 when at rest. In thisposition the power exerted by spring l2 on piston 4 is balanced by thepower exerted by spring 32 on piston l6. This is easily realized bygiving suitable values to the surfaces of pistons 4 and I6 and springsI2 and 32 (owing to their weakness the action of springs 1, 2| and 4ineed not be taken into account).

When pedal 3 is depressed, cross shaft i0 is rotated in the direction ofarrow f Lever 9 compresses spring -I2 which reduces the pressure of theliquid in proportion with the travel of the pedal. The equilibrium ofpressure in cylinder 15 is destroyed and piston i6 moves forward in thedirection of arrow f under the action of a force equal to the pressureof spring 32 less the force of the pressure of the liquid;

If the travel of the pedal is such that the small cup 6 uncovers port 5,the liquid contained in the pipe line C and in cylinders I and I5 isunder atmospheric pressure. The result is that the effort applied onpiston l6 and on rod 22 in the direction of arrow f is equal to thepressure of spring 32.

Therefore, on pedal 3 being depressed, as the pressure of the liquiddiminishes, piston i6 and rod 22 move in the direction of arrow f owingto the action of spring 32. The elements connected withyoke 25 followthis movement. For instance (Figures 3 and 4) if the yoke 25 movesupward the brake shoes 28 and 29 are pushed apart and applied againstthe drum while ensuring an equal distribution of the effort on each jaw.Moreover in cases where the device is applied to brakes actingon theunrolling system (Figure 4), the drive of one of the shoes (shoe 28 forinstance if the drum is revolving in the direction of arrow 1 causesyoke 25 which is already being driven upward by spring 32 to be drawnupward in addition by the servo-braking eiTect applied to shoes 28 and29. Shoes 28 and 29 are joined to each other at their lower ends by ashoe link pin SI and are adapted to anchor (depending upon the directionof drum rotation) upon anchor pins 92 and 93. This servo-braking effectreduces the effort to be applied to the pedal by the driver to an equalextent.

It should be noted that if a leak occurs in the pipe line C or incylinders l and [5, the pressure of the liquid drops as is the case ifone presses pedal 3 to the end of its travel so that, for instance, inthe adaptation of this device to the brakes of a vehicle a leak wouldcause immediate braking.

The same phenomenon occurs as soon as the liquid evaporates. If there isa formation of gases this gas is compressed and this reduces thepressure of the liquid. This makes it possible to employ any sort ofliquid in the apparatus. It is obvious that this device offers aguarantee of absolute safety.

When pedal 3 is released, whether port 5 has been uncovered or not bycup 6, spring l2 compresses the liquid and piston 4 is driven in the direction of arrow f until it reaches the position of equilibrium itoccupied originally, this position depending on the pressure of theliquid which, in turn, depends on the power of springs l2 and 32 and onthe surfaces of pistons 4 and I6. Piston i6 and yoke 25 also return totheir rest position releasing shoes 28 and 29 and the other organs theycontrol It will be seen that the shoes ator. It is not necessary thatthe piston 4 on the cup 6 should move to the right (Figure 1) past theport 5 every time the pedal is actuated (this is only necessary whenfilling). In order to obtain a sufiicient effort on rod 22 all that isnecessary is to cause a suitable variation in the strength of spring 32or the surface of piston l6 as compared with the section ofpiston 4 andthe strength of spring i2. It will be seen clearly that these variousvalues are equal, in actual value, to those which would be necessary forbraking by compressing the liquid as in the systems known to date, thesign alone having changed.

As has been noticed, given a balancing pressure, the moving components,and in particular ring 34, return to the same position. Should there bewear of the element controlled by yoke 25 (Figure 1), in order to retainthe same functioning conditions, for instance the same play betweenshoes 28 and 29 and the brake drum in the case of a brake, it will benecessary to reduce length XY of rod 22 by an amount in proportion tothat wear. It is for that reason and to keep the travel of the pedal 3constant that the automatic adjustment described above has beenprovided. Operation is as follows: When piston l6 moves in the directionof arrow f it actuates ring 34. Ring 37 under the action of spring 4!also moves in the same direction but rotates in the direction of arrow iowing to the fact that it is connected with plug 39 by rods 38. When thetravel of ring 34 reaches a certain value, determined in advance, ring3'! turns, in relation to ring 34, by the value of one tooth. When ring34 returns to its initial position it presses hard on ring 3! which,when it approaches plug 39, is compelled to rotate in a directionopposite to that of arrow f drawing along, in its rotating motion, ring34 and rod 22. Rod 22 therefore screws into yoke 25 and thus reduces thedistance XY between the yoke and ball joint 23 by the required amount.It isnecessary to calculate properly the pitch of teeth 35, the lengthand the displacement of rods 38 and the thread ofrod 22.

Figure 2 represents another method of realization of transmitting groupA. In the example set forth cylinder l communicates with a separate tank96 through piping 41 and a side port 5 which can be opened and shut bypiston 6. Cylinder I is closed at one end by plug 48 preferably screwedinto it, a cup 49 between the cylinder and the plug resting on ashoulder in said cylinder I. A socket 50 is pressed against this cup bya spring 5| resting on the one hand on this socket 50 and on the otherhandon the top of piston 4. The cup is thus maintained pressed againstthe center portion 52 of piston 4, and prevents any loss of the liquidcontained in the annular space 53. A port 54 in the side wall ofcylinder l places space 53 in communication with tank 46, thuspermitting the return of the liquid into this tank when piston 9 movesin a direction opposite to arrow 1 Rod II is directly articulatedpnoperating pedal 3 which is pivoted on a spindle ID. A powerful spring I2rests on the one hand on plug 48 and on the other hand on a washer 55fixed to red H in any suitable manner, the said spring urging piston 4in the direction of arrow F.

The operation of this system is the same as in the case of thearrangement described previously, the pressure of the liquid beingreduced when one depresses the pedal 3 against spring l2 in a reversedirection to arrow 1 The control system represented in Figure 5 isapplied to the front wheel of an automobile. In

a 68 of equalizing lever 61.

this example of application, cylinder I 5 is fixed to the swivellingspindle 56 of the wheel the axle of which is shown at 51 and one of thestub axles at 58. Piston I6 is cambered and cup I! made tight in such away that it cannot slide. .Operation is the same as in the example shownin Figure 1, the sliding of cup I! being replaced by the elasticdeformation of the said cup.

For preference the control system comprises an adjusting device whichpermits ofinodifying rapidly and at will, in either direction, the restposition of the moving components of the control system, while theoperating pedal retains an invariable rest position. In the examplesshown in Figures 6 to 9, pedal 3 is fitted loose on shaft l0 and bears,by means of a cam 59 which can be made fast in any desired position, ona lever 60 which is rigid with shaft l0.

Pedal 3 (Figures 6 and 7) comprises a yoke 6! in which a shaft 62 isfree to oscillate. On this shaft two toothed wheels 63 and 64, are fixedand, preferably between these two wheels is provided a cam 59. Wheel 63which is not shown on Figure 6, bears teeth placed in an inverseposition to those on wheel 64. A push rod 65 placed towards the top cancontrol wheel 64 and another rod 66 placed towards the bottom cancontrol wheel 63. These two rods are articulated to an equalizing lev 61comprising two plates 68 and Hand itse f articulated at 16 'so that itcan oscillate in the direction of arrows f and f. Two springs H guidedby rods 65 and 66, rest at one end i on, a floor or base 12 and at theother end on the ends of equalizing lever 61, urging the latter to itsrest position. A fixed openings through the floorboard 12 are sumcientlylarge to permit the operation of the rods 65 and 66 without jamming.

The adjustment of the control element is modified as follows: Depressionof end 69 of the equalizing lever 61 pushes rod 65 thereby causing wheel64 to rotate and consequently cam 59 in the direction of arrow I. Owingto the shape of the cam, lever fifl comes nearer pedal 3 and drivesshaft ID in a direction reverse to arrow f This causes a displacement ofpiston 4 in the direction of arrow f an increase in the pressure of thetransmitting liquid, and a displacement of piston l6, rod 22 and yoke 25in a direction contrary to that of arrow f displacement is to bring jaws28 and 29 (Figures 3 and 4) nearer one another thus reducing the playbetween the said jaws and the brake drum. It is thus possible, from thedriver's seat and even while the car is moving, to loosen the brakesshould they remain on. v It is also possible to reduce the play betweenjaws 28 and 29 and the brake, in the contrary All one has to do is topress on the end Rod 56, acts onthe toothed wheel 63 and causes it torotate, as well as cam 59, in a direction contrary to that of arrow iLever 60 moves away from pedal 3 and makes shaft l0 rotate and thiscauses a reduction of pressure in the transmitting liquid and thedisplacement of the yoke in the direction of arrow f.

Figures 8 and 9 represent a similar arrangement in which the control ofcam 59 is efiected case.

by chains or cables and by hand. In this ar- The effect of this toothedwheel 18.

of shaft 62, the ends of two cables and I6 are attached and their otherends are attached to the ends of a chain 11 which passes over a A handle19 is solid with wheel 18. Handle 19, wheel 18 and chain 11 may beplaced, for instance, on the dash of the car. The cables 15 and 16 arecarriedon one or more idler pulleys 80. They also pass through thegrooves 8| and 82 of pedal 3 so that in its rotation this pedal may notinfluence the length of the cables and consequently the adjustment.Operation is the same as in the preceding case. It is suflicient to turnhandle I9. one way orthe other.

While there has been shown and described one embodiment of theinvention, it is to be understood that the invention is not'limitedthereto.

be resorted to without departing from the scope of the invention, aswill occur to those skilled in the art. Reference will therefore behad'to the appended claims for a definition of the limits of theinvention. 1

This application is a division of my co-pending application Serial No.546,342, filed June 23, 1931.

I claim:

1. A brake comprising a drum, a backing plate, a friction member, asupport on the backing plate, a threaded rod longitudinally slidable toapply the friction member to the drum, a threaded sleeve connected tothe friction member into which sleeve the threaded end of the rod isadapted to be screwed, a toothed collar secured to the rod, a secondtoothed collar slidable on and rotatable on the rod, and links pivotallyconnected to the support and to .the second collar. I

2. A brake comprising a drum, a backing plate, a friction member withinsaid drum, a cylindrical support member secured to the backing plate, athreaded rod slidable longitudinally in said cylindrical member to applythe friction member, a threaded sleeve connected to the triotion memberinto which sleeve the rod is adapted to be screwed, a toothed collarsecured to the rod, a toothed collar slidable and rotatable on the rod,and links pivotally connected to the cylindrical member and to thesecond collar.

3. A brake comprising a, drum, a backing plate,

a friction member within the drum, a support mounted on the backingplate, a threaded rod longitudinally slidable to apply the frictionmember to the drum, a threaded sleeve connected to the friction memberinto which sleeve the rod is adapted to be screwed, a toothed membersecured to the rod, a second toothed member slidable and rotatable onthe rod, and links pivotally connected to the support and to the secondtoothed member. i

' ROBERT CHARLES LOUIS RIERRE TURGOT.

